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Philippe Bugnon

Cette personne a quitté l’EPFL

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Publications associées (31)

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Structural and electronic implications for carrier injection into organic semiconductors

Philippe Bugnon, Mauro Castellani

We report on the structural and electronic interface formation between ITO (indium-tin-oxide) and prototypical organic small molecular semiconductors, i.e., CuPc (copper phthalocyanine) and alpha-NPD (N,N'-di(naphtalen-1-yl)-N,N'-diphenyl-benzidine). In pa ...

Springer Verlag2009

Bulk diffusive relaxation mechanisms in optically excited topological insulators

Helmuth Berger, Arnaud Magrez, Philippe Bugnon, Alberto Crepaldi

The possibility to inject spin currents in topological insulators (TIs) by ultrashort optical pulses has stimulated intense studies of their out-of-equilibrium electronic properties. However, a comprehensive description of the electronic relaxation dynamic ...

Amer Physical Soc2017

Dirac nodal lines and flat-band surface state in the functional oxide RuO2

Helmuth Berger, Arnaud Magrez, Simon Karl Moser, Philippe Bugnon

The efficiency and stability of RuO2 in electrocatalysis has made this material a subject of intense fundamental and industrial interest. The surface functionality is rooted in its electronic and magnetic properties, determined by a complex interplay of la ...

AMER PHYSICAL SOC2018

Momentum-Resolved Spin Dynamics of Bulk and Surface Excited States in the Topological Insulator Bi2Se3

Helmuth Berger, Marco Grioni, Philippe Bugnon, Alberto Crepaldi

The prospect of optically inducing and controlling a spin-polarized current in spintronic devices has generated wide interest in the out-of-equilibrium electronic and spin structure of topological insulators. In this Letter we show that only measuring the ...

Amer Physical Soc2015

Momentum and photon energy dependence of the circular dichroic photoemission in the bulk Rashba semiconductors BiTeX (X = I, Br, Cl)

Helmuth Berger, Arnaud Magrez, Marco Grioni, Oleg Yazyev, Philippe Bugnon, Alberto Crepaldi, Luca Moreschini, Gabriel Albert Autes, Jens Christian Johannsen, Cédric Tournier-Colletta

Bulk Rashba systems BiTeX (X = I, Br, Cl) are emerging as important candidates for developing spintronics devices because of the coexistence of spin-split bulk and surface states, along with the ambipolar character of the surface charge carriers. The need ...

American Physical Society2014

Crystallization and Organic Field-Effect Transistor Performance of a Hydrogen-Bonded Quaterthiophene

Rosario Scopelliti, Anne-Clémence Corminboeuf, Holger Frauenrath, Philippe Bugnon, Stéphane Suarez, Riccardo Petraglia, Jan Gebers, Bilal Özen, Piotr De Silva

Crystalline thin films of pi-conjugated molecules are relevant as the active layers in organic electronic devices. Therefore, materials with enhanced control over the supramolecular arrangement, crystallinity, and thin-film morphology are desirable. Herein ...

2020

Optical properties of BiTeBr and BiTeCl

Helmuth Berger, Arnaud Magrez, Philippe Bugnon, Ana Akrap

We present a comparative study of the optical properties-reflectance, transmission, and optical conductivity- and Raman spectra of two layered bismuth-tellurohalides BiTeBr and BiTeCl at 300 and 5 K, for light polarized in the a-b planes. Despite different ...

Amer Physical Soc2014

Ultrafast photodoping and effective Fermi-Dirac distribution of the Dirac particles in Bi2Se3

Klaus Kern, Helmuth Berger, Marco Grioni, Philippe Bugnon, Alberto Crepaldi

We exploit time- and angle-resolved photoemission spectroscopy to determine the evolution of the out-of-equilibrium electronic structure of the topological insulator Bi2Se3. The response of the Fermi-Dirac distribution to ultrashort IR laser pulses has bee ...

Amer Physical Soc2012

Time-resolved ARPES at LACUS: Band Structure and Ultrafast Electron Dynamics of Solids

Majed Chergui, Helmuth Berger, Arnaud Magrez, Marco Grioni, Frank van Mourik, Alberto Crepaldi, Christopher Alexander Arrell, Philippe Bugnon, Gianmarco Gatti, José Javier Pancracio Ojeda Andara, Silvan Dino Marcos Roth

The manipulation of the electronic properties of solids by light is an exciting goal, which requires knowledge of the electronic structure with energy, momentum and temporal resolution. Time- and angle-resolved photoemission spectroscopy (tr-ARPES) is the ...

2017

Unusual Shubnikov-de Haas oscillations in BiTeCl

Helmuth Berger, Arnaud Magrez, Philippe Bugnon

We report measurements of Shubnikov-de Haas oscillations in single crystals of BiTeCl at magnetic fields up to 31 T and at temperatures as low as 0.4 K. Two oscillation frequencies were resolved at the lowest temperatures, F-1 = 65 +/- 4 T and F-2 = 156 +/ ...

Amer Physical Soc2014

Experimental determination of the bulk Rashba parameters in BiTeBr

Helmuth Berger, Arnaud Magrez, Philippe Bugnon

Shubnikov-de Haas (SdH) oscillations, Hall effect, and optical reflectance (R(omega)) measurements have been performed on single crystals of BiTeBr. Under magnetic fields up to 32 tesla and at temperatures as low as 0.4K, the SdH data shows a single oscill ...

IOP Publishing - EPL Association2016

Persistence of a surface state arc in the topologically trivial phase of MoTe2

Helmuth Berger, Arnaud Magrez, Oleg Yazyev, Marco Grioni, Philippe Bugnon, Alberto Crepaldi, Gabriel Albert Autes

The prediction of Weyl fermions in the low-temperature noncentrosymmetric 1T' phase of MoTe2 still awaits clear experimental confirmation. Here, we report angle-resolved photoemission (ARPES) data and ab initio calculations that reveal a surface state arc ...

Amer Physical Soc2017

Efficient blue light-emitting diodes based on a classical "push-pull" architecture molecule 4,4 prime -di-(2-(2,5- dimethoxyphenyl)ethenyl)-2,2 prime -bipyridine

Michael Graetzel, Mohammad Khaja Nazeeruddin, Rosario Scopelliti, Libero Zuppiroli, Philippe Bugnon, Detlef Berner, Mauro Castellani

A novel, highly blue luminescent molecule containing donor and acceptor groups, 4,4 prime -di-(2-(2,5-dimethoxyphenyl)ethenyl)-2,2 prime -bipyridine, that shows photoluminescence emission at 450 nm with 43% quantum yield is designed and synthesized. Time d ...

Royal Society of Chemistry2006

Evidence for a Strong Topological Insulator Phase in ZrTe5

Helmuth Berger, Arnaud Magrez, Oleg Yazyev, Philippe Bugnon, Alberto Crepaldi, Gabriel Albert Autes, Luca Gragnaniello

The complex electronic properties of ZrTe5 have recently stimulated in-depth investigations that assigned this material to either a topological insulator or a 3D Dirac semimetal phase. Here we report a comprehensive experimental and theoretical study of bo ...

Amer Physical Soc2016

Electronic Phase Separation and Dramatic Inverse Band Renormalization in the Mixed-Valence Cuprate LiCu2O2

Helmuth Berger, Arnaud Magrez, Marco Grioni, Philippe Bugnon, Luca Moreschini, Simon Karl Moser, Gianmarco Gatti

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu2O2, a mixed-valence cuprate where planes of Cu(I) (3d(10)) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d(9)) chains. We find ...

Amer Physical Soc2017

Light-induced charge transfer at the CH3NH3PbI3/TiO2 interface-a low-temperature photo-electron paramagnetic resonance assay

László Forró, Andrzej Sienkiewicz, Bálint Náfrádi, Endre Horvath, Márton Kollár, Philippe Bugnon, Péter Szirmai, Pavao Roko Andricevic, Lidia Rocoffort de Vinnière, Anastasiia Glushkova, Konstantins Mantulnikovs

The performance of organic-inorganic metal halide perovskites-based (MHPs) photovoltaic devices critically depends on the design and material properties of the interface between the light-harvesting MHP layer and the electron transport layer (ETL). Therefo ...

2020

Atomic and electronic structure of a Rashba p-n junction at the BiTeI surface

Helmuth Berger, Marco Grioni, Oleg Yazyev, Philippe Bugnon, Gabriel Albert Autes, Cédric Tournier-Colletta

The non-centro-symmetric semiconductor BiTeI exhibits two distinct surface terminations that support spin-split Rashba surface states. Their ambipolarity can be exploited for creating spin-polarized p-n junctions at the boundaries between domains with diff ...

American Physical Society2014

Ultrafast Optical Control of the Electronic Properties of ZrTe5

Helmuth Berger, Arnaud Magrez, Marco Grioni, Philippe Bugnon, Alberto Crepaldi

We report on the temperature dependence of the ZrTe5 electronic properties, studied at equilibrium and out of equilibrium, by means of time and angle resolved photoelectron spectroscopy. Our results unveil the dependence of the electronic band structure ac ...

Amer Physical Soc2015

Giant Ambipolar Rashba Effect in the Semiconductor BiTeI

Klaus Kern, Helmuth Berger, Marco Grioni, Oleg Yazyev, Philippe Bugnon, Alberto Crepaldi, Luca Moreschini, Gabriel Albert Autes, Simon Karl Moser, Naunidh Singh Virk, Cédric Tournier-Colletta

We observe a giant spin-orbit splitting in the bulk and surface states of the noncentrosymmetric semiconductor BiTeI. We show that the Fermi level can be placed in the valence or in the conduction band by controlling the surface termination. In both cases, ...

Amer Physical Soc2012

Engineering the topological surface states in the (Sb2)m−Sb2Te3(m=0–3) superlattice serie

Helmuth Berger, Arnaud Magrez, Marco Grioni, Oleg Yazyev, Philippe Bugnon, Alberto Crepaldi, Gabriel Albert Autes, Simon Karl Moser, Jens Christian Johannsen

We investigate the evolution of both the occupied and unoccupied electronic structure in representative compounds of the infinitely adaptive superlattice series (Sb2)m−Sb2Te3 (m=0–3) by means of angle-resolved photoemission spectroscopy and time-delayed tw ...

Amer Physical Soc2015